id go downtown(2 blocks away, and its only about 3 blocks wide, in the center of all neighborhoods.) then go to the roof of the civic theater, with a rifle, and pick them off. id bring a radio, and a lot of food. all the stores in my town are connected with underground tunnels, but they have walls and carpeting, so if the theater gets overrun, ill go to the next store.
My home town, Grants pass, Is a rather large town, with three bridges connecting each half of the city that are on both sides of the rouge river.
honestly, like someone said, it depends on how many survivors are in your party. if its just you, then it'll take forever to clear a large town or city of the undead. However, if you have a good number of people at your back, then taking a town back varies on what strategy you use.
well taking back a city unless you have put up a fence around it is useless anyways because more will just keep comeing I think i would start by building a wall around it and then work on killing after